In the fiber optics field, the need frequently arises to connect or disconnect connectors and adapters in both single channel and multiple channel connectors and adapters. The invention here disclosed applies primarily to multiple fiber applications. There is a continuously increasing demand for higher density interconnect systems in fiber optics applications, especially in those cases where multiple fiber connectors or multiple fiber ferrules are not conveniently reachable due to small size, routing or other considerations.
In the fiber optics field, the need frequently arises to transfer light from one fiber to another either permanently or temporarily. Optical connector plugs or connectors are one of the solutions used for this purpose. Fibers terminated with optical connector plugs can be coupled together and disconnected when necessary, either to end the connection or to route the light to a different fiber. Optical connector plugs can be of the single or multiple fiber variety. Single fiber connector plugs (simplex connector plugs) provide the connection of only one fiber to another single fiber. In multiple fiber connector plugs, several fibers are simultaneously coupled with another set of similar fibers. The invention here disclosed applies primarily to multi-fiber applications.
Traditionally, in multi-fiber connectors, the connection is achieved by the use of MT-type ferrules. The ferrules, which may be manufactured mostly from plastic, have a number of channels of a diameter slightly larger than the optical fiber. It is appreciated that the ferrules may be manufactured from materials other than plastic including, but not limited to ceramics, metal and glass and not depart from the scope of the present invention. In use, the optical fibers are inserted into the channels and maintained fixed therein by the use of adhesives such as, but not limited to, epoxy, or mechanical clamping. The ends of the fibers are preferably made to be flat or protrude slightly from the end surfaces of the ferrule and are then terminated, generally by a polishing procedure or other means that provides a very smooth surface of optical quality.
Two connectors may be mated using an adapter. Each connector preferably comprises the ferrule and a ferrule holder. One of the two mated connectors usually has a ferrule with a pair of alignment pins, while the other connector has a ferrule with a pair of alignment holes. Modern fiber optic connectors usually have a spring mechanism that pushes the ferrules towards one another with a controlled force in order to achieve physical contact of both of the ferrules' ends, thereby improving the optical performance of the connection.
The termination or polishing of the fiber ends is a very involved and delicate procedure which results in the fiber position being either slightly below or above the ferrule end-face surface. The protrusion of the fibers from the ferrule end has to be controlled to very tight tolerances in order to avoid damage of the fiber ends when in physical contact. The pressure between fibers has to be kept in a narrow range in order to keep the glass in its elastic region and thereby prevent fiber rupture as well as preventing the movement of the fibers inside the ferrule channels (pistoning) when the two connectors are mated. It is also very important to obtain a very smooth surface free of scratches and other defects, especially in the central core section of the fiber where the light travels. In particular, since ferrule ends and fibers are preferably polished together, it is necessary to prevent released ferrule material from damaging the fiber ends during this procedure.
Keeping fiber optic connector plugs free from contaminants such as dirt or dust is also very important. Dirt or dust on fiber ends can scatter or absorb light, causing excessive loss of signal and corresponding poor system performance. Presence of contaminants inside the connector plug could cause misalignment with similar consequences. Likewise, because of the intensity of the light being transferred, it is important to shelter users from unintended viewing thereof, so as to prevent eye injury.
There is also a continuously increasing demand for higher density interconnect systems in fiber optics applications. The introduction by the present invention of a multi-fiber connector with the standard MT type ferrule has resulted in a small multi-fiber connector/adapter system with a push-push mechanism that allows for very high density configurations.